Ergonomics and Job Design
What is Ergonomics?
The scientific study of human work. It considers the physical and mental capabilities and
limits of the worker as she/he interacts with tools, equipment, work methods, tasks and
the working environment.
What are the goals of ergonomic job design?
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reduce work related muscoloskeletal disorders by adapting the work to fit the
person, instead of forcing the person to adapt to the work
reduce safety hazards, absenteeism due to work injury, and related worker’s
compensation claims
improve productivity through development of more efficient work methods
reduce cost of employee training
improve employee relations
What are the elements of an Ergonomics program?
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Worksite Analysis
Hazard Prevention and Control
Medical Management
Training and Education
What are some of the symptoms of musculoskeletal
disorders that work site analysis may reveal?
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painful joints
pain in wrist, shoulders, forearms, knees, etc.
pain, tingling or numbness in hands and feet
fingers or toes turning white
shooting or stabbing pains in arms and legs
back and neck pain
swelling or inflammation
stiffness
burning sensations
heaviness
weakness or clumsiness in hands
What are the common risk factors to look for during
work site analysis?
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Forcefulness
Awkward position
Repetitiveness
Static loading or sustained exertions
Mechanical contact stress
Extreme temperatures and hand-arm vibration
Poorly fitted gloves
How do you identify the causes of risk factors?
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the method used or required to do the task
the effort or strength required to do the task
the location of the parts, equipment or tools
the position of parts, equipment or tools
the speed or frequency of the work
the duration or repetition of the tasks
the design of the parts, equipment or tools
the environmental factors such as light, noise, temperature, and air quality
What types of hazard prevention and controls can be
implemented?
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Engineering controls
Work practice controls
Personal protective equipment
What are Engineering controls?
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Involve making changes to workstations, tools and equipment used on the job, or
changing the way a job is done.
These controls are preferred over all others because they make permanent changes
that eliminate the hazard at the source.
Include workstation design, work methods design, tool/equipment design,
controls and displays, and product design.
What engineering controls relate to workstation design?
Principles of Motion Economy
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Hand motions
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Basic motion types
Location of parts and tools
Release the hands of as muck work as possible
Use gravity
Operator considerations
What are Work Practice controls?
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Work methods training
Gradual introduction to work
Recovery pauses
Job rotation
Job design
Maintenance and housekeeping
Check out the Ergonomics Case Study The Buttered Sole Line
from the Canadian Centre for Occupational Health and
Safety, www.ccohs.ca What are the risk factors of spreading?
Prolonged standing in a stooped position, repetitious reaching
forward and twisting of the body put workers at high risk for
low back injury. Working with arms elevated above the waist
level, and having no control over the pace of work pose a
considerable risk for injuries of the neck, shoulder and arms.
Standing on a hard floor and having limited flexibility of body
posture can cause lower leg discomfort. How can the risk
factors be reduced? Workers exposed to repetitive movements
and awkward body positions. Provide shorter workers with
platforms so that they can spread the fish with their arms
below waist level. Provide enough foot clearance to allow
workers to get as close as possible to the conveyor. Provide a
foot rest to allow workers to shift their body weight. A
sit/stand stool would reduce the stress on the legs and back
due to prolonged standing. Also, wearing gloves when
handling frozen fish would reduce the chance of losing manual
dexterity from the cold. What is Wrapping? The wrapping of
boxes is carried out by two workers using two sealing
machines. Each worker processes about 3,000 boxes every
shift. To complete the task, a worker has to: twist the body to
the left to reach for the box on the conveyor twist the body to
the right to insert box into cellophane bag press control
button to activate sealer The task lasts approximately five
seconds and is carried out while standing. What are the risk
factors? The wrapping job poses a risk for repetitive motion
injuries because of the poor layout of the work station, the fast
pace of work dictated by the speed of the conveyor, and the
design of the task, that does not allow workers to change
activities throughout the whole shift. Workers are at risk for
neck, shoulder and upper arm injuries because of restricted
flexibility of body positions, highly repetitious movements of
both arms above waist level and repetitive reaching sideways.
Highly repetitive and forceful movements while handling one
kilogram boxes with only one hand are very hazardous to the
wrists. Prolonged standing and frequent twisting create
hazards for low back and lower leg injuries. How can the risk
factors be reduced? Workers are exposed to repetitive and
forceful movements and awkward body positions. Workers
should pick up boxes with their arms at waist level. Shorter
workers should use a platform. To reduce reaching sideways,
it may be necessary to modify the flow of the conveyor.
Workers should have enough foot clearance so that they can
get close to the work bench and a foot rest to shift their body
weight. Providing workers with anti-fatigue matting and a
sit/stand stool would release stress on their legs and back due
to prolonged standing.